Astronomers using the Hubble Space Telescope have discovered Pluto's fifth moon, a little more than three years before a NASA space probe is due to sail past the dwarf planet and its tribe of satellites.The irregular moon, estimated to be 6 to 15 miles (10 to 25 kilometers) acro …

M. Showalter / SETI Institute / NASA / ESAThis photo from the Hubble Space Telescope shows Pluto and its five known moons, including a newly discovered satellite indicated as P5. Its provisional name is S/2012 (134340) 1.By Alan Boyle

Follow @b0yleAstronomers using the Hubble Space Telescope have discovered Pluto's fifth moon, a little more than three years before a NASA space probe is due to sail past the dwarf planet and its tribe of satellites.The irregular moon, estimated to be 6 to 15 miles (10 to 25 kilometers) across, was found in the course of checking out the potential collision hazards facing NASA's New Horizons spacecraft for the Bastille Day flyby on July 14, 2015. "The inventory of the Pluto system we're taking now with Hubble will help the New Horizons team design a safer trajectory for the spacecraft," the mission's principal investigator, Alan Stern of the ...